This case study takes place at a fictional biotechnology company developing herbicides against invasive plant species. The case study focuses on five herbicides with different effects on photosynthesis. Students play the role of lab interns and explore photosynthesis and the herbicide effects by engaging in concept mapping, experimental design, data manipulation, and data analysis. The goal is to use the experimental data to predict the steps in photosynthesis that are inhibited by each herbicide. Students should come away from the case study with a process-based understanding of photosynthesis. This case study is designed for the "flipped" classroom with suggested preparatory videos and associated assessment questions included. Videos can be supplemented with textbook readings or mini-lectures. This activity was developed for a non-majors introductory biology course but it could also be used in any general biology course, including majors' courses. It might also be used to establish foundational knowledge for more advanced discussions of photosynthesis in plant biology (botany) courses.